fitLWauto function

Best Fit Using Litchfield and Wilcoxon Evaluation of Dose-Effect Experiments

Use optimization to describe the best fitting line to a dose-effect experiment following the methods of Litchfield and Wilcoxon (1949).

fitLWauto(DEdata)

Arguments

• DEdata: A data frame of dose-effect data (typically, the output from dataprep) containing at least eight variables: dose, ntot, nfx, pfx, log10dose, bitpfx, fxcateg, and LWkeep (see Details).

Returns

A numeric vector of length two, the estimated intercept and slope of the dose-response curve on the log10-probit scale,

Details

The input data are expected to be summarized by dose. If duplicate doses are provided, an error will be thrown.

Examples

dose <- c(0.0625, 0.125, 0.25, 0.5, 1)
ntested <- rep(8, 5)
nalive <- c(1, 4, 4, 7, 8)
mydat <- dataprep(dose=dose, ntot=ntested, nfx=nalive)
mydat
fitLWauto(mydat)

References

Litchfield, JT Jr. and F Wilcoxon. 1949. A simplified method of evaluating dose-effect experiments. Journal of Pharmacology and Experimental Therapeutics 96(2):99-113. [link].